The present invention relates to a method and apparatus for effectuating dynamic soil compaction by impacting the soil with vibrating masses of compacting equipment such as vibration rollers, plate vibrators, tampers, or the like.
Such procedures are known to be used for compacting fill or mixtures in earthwork, underground construction and road construction. Depending on the type of equipment employed, the vibrating masses may be subjected to vertical oscillations or may be driven by rotating eccentric weights. The latter are mainly employed in vibration rollers, which are currently in widespread use and are suitable for all compaction work, and in which one or more roller members roll over the surface to be compacted, while dynamic vibratory forces act on the roller members to produce a compaction effect which is substantially greater than if the roller acts only with its own weight.
Other types of vibrators are known, such as plate vibrators and tampers, in which, generally, the mass of the compacting tool vibrates with a certain frequency and amplitude against the frame containing the remaining structural components, but are to a large extent limited in their use and are mainly used for lighter and less extensive compaction requirements.
All previously known methods and apparatus for dynamic soil compaction have the disadvantage that the time for which the instrument is to be used in practice to achieve a required degrees of compaction is not exactly determined, and empirical values must be relied on. Continuous measurement of the soil compaction obtained, e.g. by way of the Proctor density, is not possible at the building site because of the cost, and it is necessary for safety reasons to provide a safety factor i.e., to provide an additional number of working runs, e.g. roller passes to assure that final compaction is sufficient to produce the requisite structural support. These additional runs not only result in operating costs which are unnecessarily high from the point of view of the degree of compaction, but actually create the danger of reloosening the soil.